Method of sharpening the grinding disc in a grinding machine



Oct. 8, 1968 G, GLUCHOWICZ 3,404,670 METHOD OF SHARPENING THE GRINDING DISC IN A GRINDING MACHINE Filed Jun: 14, 1965 FILTER AMPLIFIER DISC DISC ADVANCE RETRACT INVENTOR GERSZON GLUCIHOWICZ BY mORNEY United States Patent 3,404,670 METHOD OF SHARPENING THE GRINDING DISC IN A GRINDING MACHINE Gerszon Gluchowicz, 21 Radmansgatan, Stockholm, Sweden Filed June 14, 1965, Ser. No. 463,939 Claims priority, application Sweden, July 8, 1964, 8,347/ 64 3 Claims. (Cl. 125-11) ABSTRACT OF THE DISCLOSURE- During the dressing of a rotatable grinding disc, 21 feeler, which is connected to the diamond tool holder, senses the vibrations of the holder, and transforms them into electrical signals, the potential of which is proportional to the depth to which the tool penetrates the surface of the disc. These signals are used to effect a corresponding adjustment in the cutting depth of the tool, when necessary.

This invention relates to a method of sharpening the grinding disc in a grinding machine.

More particularly this invention relates to a method of sharpening the rotatable grinding disc in a grinding machine by means of a sharpening tool supported by a holder and usually containing a diamond tip. This sharpening has for its object to restore with even intervals the form of the grinding surface of the grinding disc with the intention of removing the dull abrasive grains from its surface, and also to restore the generatrix of the grinding disc, which is in contact with the rotatable workpiece, to a predetermined position in the machine. After the sharpening operation the grinding disc is fed towards the workpiece until final dimension is obtained on the worked surface thereof.

The grinding disc or the workpiece is mounted on a transverse sliding carriage which is actuated by a feeding device transverse to the axis of rotation of said disc or said workpiece. After the grinding of a workpiece has been finished the transverse sliding carriage returns to a starting position. Before the grinding disc is subjected to a sharpening treatment it is reset relatively to the diamond in the transverse direction in such a manner that the diamond will cut off a certain layer of the grinding disc. This complement in the resetting of the grinding disc, which is also denominated compensation, means that the grinding disc is conducted past the diamond, as viewed radially, to an extent which is greater than the wear or abrasion which takes place between each sharpening operation. The diamond in turn can be actuated so as to be caused to occupy an exact position within the machine, as shown, for example, in the US. Patent No. 3,003,293.

The magnitude of the complement or compensation has in the past been determined so as always to exceed the wear on the grinding disc, since said wear was hitherto impossible to determine. All this has resulted in that the consumption of grinding disc material usually has been too great. It is one main object of the invention to provide means to be used in connection with grinding machines rendering it possible to eliminate such unnecessary waste of grinding disc material.

A further object of the invention is to provide a feeling or scanning member responsive to an actuation of the holder treated by the sharpening operation proper and adapted to produce a voltage which is dependent on the magnitude of the sharpening depth and which is utilized for reading the sharpening depth and/ or adjustment thereof to a desired value.

A still further object of the invention is to provide a 3,404,670 Patented Oct. 8, 1968 the dressing of a grinding disc may be sensed according to this invention.

Referring now to the drawing, the feeling or scanning member 10 may be a vibrationor wire-elongation pickup or the like, which is engaged with a dressing tool such as a conventional diamond holder 12, so that it develops an electronic potential as the result of the vibrations of the diamond holder. The magnitude of the vibrations and that of the potential is proportional to the depth to which the tool 12 penetrates the surface of the grinding disc 14 during a dressing operation, and follows a curve which normally is not linear. During the sharpening operation the diamond holder 12 which may have the form of an arm is thus subjected to oscillations having a frequency which is characteristic for the sharpening moment and does not appear anywhere else. The oscillations correspond to the reasonant frequency or the frequency of impacts of the corns of the grinding disc against the diamond tip. Simultaneously, disturbing frequencies which have nothing to do with the sharpening operation proper and thus appear, also when the diamond is out of operation, are filtered off. The impulses from the feeling or scanning device 10 pass through an adjustable band pass filter 16, which may be adjusted to that frequency which produces the greatest voltage and which is then coupled to an amplifier 18 which in turn drives a pointer indicating instrument 20, for example. By means of a potentiometer 22 the sensibility can then be adjusted in every occurring case in such a manner that full deflection is indicated on the scale 20, when the sharpening is unnecessarily great. The output potential from the amplifier may in addition be coupled to two current relays 24 and 25, one of them being adapted to deliver a signal when the deflections are too small and the other to deliver a signal when the deflections are too great. These impulses may in turn actuate setting members 26 and 27 of the machine for control and adjusting of the magnitude of the complement or compensation.

One is now in a position to observe during the grinding operation proper the deflections from the pointer indicating instrument and to adjust the complement or compensation to an optimum value regarding the degree of utilization of the grinding disc. Further one has a possibility of switching impulses from the maximum and minimum indicating relays to setting members which automatically reset the complement or compensation to the most favorable value thereby affording the grinding disc the longest possible life.

Under some conditions the grinding disc may be worn too much due to a faulty workpiece requiring exceptional grinding increases. As a consequence thereof the grinding disc is not sharpened by the diamond and the plurality of subsequent workpieces is ground in a faulty manner. To avoid this inconvenience one may also utilize the minimum impulses to actuate the machine to repeat the sharpening step until a sufficient sharpening effect takes place whereupon the machine continues with its working cycle.

The figure illustrates schematically one way in which What I claim is:

1. A method of sharpening the grinding disc in a grinding machine by means of a dressing tool supported by a holder and preferably containing a diamond tip, said tool and said grinding disc prior to each grinding opera.- tion being reset in relationship to one another to a position in which a removal of disc material will take place, sensing the frequency of the vibration of the holder created by the dressing operation, causing the frequency of the vibrations to produce a potential which is dependent 0n the magnitude of the dressing depth, and applying the potential to a meter for reading the dressing depth.

2. A method of dressing the grinding disc in a grinding machine by means of a dressing tool supported by a holder and preferably containing a diamond tip, said tool and said grinding disc prior to each grinding operation being reset in relationship to one another to a position in which a removal of disc material will take place, detecting the frequency of the vibration of the holder created by the dressing operation by means of a feeling member,

, producing a potential which is dependent on the magnitude of the dressing depth, and adajusti-ng the dressing depth to a desired value.

3. The method of claim 2 including reactuating the dressing operation, when the potential developed during a given dressing operation falls below a predetermined minimum value. p I

References Cited UNITED STATES PATENTS 9/1943 Kuehni 7378 X 2,360,639 10/1944 Asirnow 82- -34 X 2,408,012 9/1946 Williams 7378 X 2,498,881 2/1950 Elridge 2 82-34 X 3,003,293 10/1961 Gluchowicz 51165 3,116,632 1/1964 Lane 125 11 X 3,214,965 11/1965 Wellborri' 125 -11 X HAROLD D. WHITEHEAD, Primary Examiner. 

